Science in Society Archive

Cutting Down on Sugar

We consume far too much sugar, especially the so-called free sugars; but will the government stand up to the food industry and take measures to reduce our intake? Prof Peter Saunders

While sugar has always been part of the human diet, it is only in modern times that we have started to consume large amounts of free sugars, i.e. sugars that have been to some extent refined. This includes the sugar that we add when we are cooking or put into our tea or coffee, and the surprisingly large amounts that manufacturers add to soft drinks, sweets and also other foods we don’t generally think of as sweet, such as many ready-made meals. A tablespoon of ketchup contains roughly a teaspoon of free sugar and a single tin of soft drink may contain as much as ten teaspoons. The sugars in fruit juice and honey are also free; in honey the refining has been done by the bees.

Free sugars have to be considered separately from those naturally present in fully unrefined forms because they have a greater effect on health. The World Health Organization (WHO) has concluded that consuming large amounts of free sugars increases the risk of obesity and dental caries and also of diseases associated with being overweight such as Type 2 diabetes. It has made the firm recommendation that we should reduce our daily intake of free sugars to less than 10 % of our total energy intake. It has also made a conditional recommendation that the proportion should be less than 5 %. It is less prescriptive about the lower limit because there are so few populations with such low intakes and consequently few if any epidemiological studies to back up the scientific evidence [1].

The government’s Scientific Advisory Committee on Nutrition (SACN) has recommended accepting the 5 % limit. This would mean a total of intake of free sugars of 30 g or about 6 teaspoons for anyone 11 years or older; less for young children [2]. Currently sugar accounts for about 15% of the mean intake of energy for school-aged children and teenagers [3], so this would be a considerable reduction.

The government has accepted the SACN’s recommendations. What remains to be seen is whether it acts on them.

Why concentrate on sugar?

The food industry naturally objects to the WHO recommendations and has been lobbying against them. They generally rely on two supposedly scientific arguments. First, they claim the real problem is not too much food but too little exercise. Second, if we are going to eat less, there is no reason to single out sugars in general and soft drinks in particular. Calories, after all, are just calories, and it doesn’t matter where they come from. Thus, they argue, if you drink a tin of Coca-Cola, which contains 139 calories [4], that’s the same as eating two slices of whole wheat bread and in either case you only have to go for a 20 minute brisk walk to burn it off.

Neither argument stands up. Think how hard it can be to lose a few pounds, and if you do, how hard it is to keep yourself from gaining it back. That is because there are mechanisms that actively regulate your weight. It’s as though your body decides what your weight should be, and does its best to counter any change in how much you eat or how active you are. So it’s not just a matter of subtracting the energy you use in exercise from the calories in the food you eat. The question is also about how what you eat and what you do affect the weight controlling mechanisms, and despite years of research we still have only a partial understanding of them.

According to the US Department of Agriculture, Americans consumed on average 300 more calories a day in 2000 than in 1985 [5]. There’s no reason to suppose they were more physically active, so taking a pound of fat as equivalent to about 3 500 calories, by 2000 they ought to have been putting on weight at about 30 pounds a year. Like many other people, Americans are getting fatter, but not at that rate. Conversely, walking for an extra 20 minutes every day isn’t going to take 15 pounds off if you keep it up for a year, whatever the food industry says.

While we don’t yet know how weight is regulated, we do understand how some of the mechanisms work. For example, when your blood glucose is low, you feel hungry. After you have eaten, your blood glucose rises and you no longer feel hungry, so you stop eating. This clearly contributes to matching your food intake to the amount of energy you are using.

The rise in blood sugar does not, however, depend only on the number of calories in your meal. To allow for this, nutritionists have developed the glycaemic index (GI), a ranking of carbohydrates according to the extent to which they raise blood sugar levels after being eaten [6]. High GI foods such as those containing free sugars and also potatoes, white bread and white rice, are broken down quickly and cause rapid increases and then decreases in blood sugar. Low GI foods, including most fruit and vegetables, pulses and wholegrain foods, are digested and absorbed slowly, and the rises and falls in

blood sugar are smaller and slower. That makes these foods better for weight control because they help control appetite and delay hunger. They are also better for diabetics, by the way, because they also do not cause large increases in insulin levels [6].

This illustrates why free sugars have been so important in the rise of obesity. The worldwide increase in the consumption of soft drinks has been especially important because we seem to be able to drink large quantities without dulling our appetites. This has been especially relevant in Mexico, which has an especially high rate of consumption of soft drinks and where obesity is rising faster than anywhere else in the world [7].

Your weight is also affected by your gut microbiota, the 100 trillion or so microbes that live in your gastrointestinal tract. These are responsible for a significant fraction of your energy intake because some of them break down foods that would otherwise be indigestible. The proportions of the different species are largely determined in the first three years of life (another reason why we should be careful about giving antibiotics to infants) but they are also affected by your diet as an adult, which makes this another way in which it’s not just the number of calories that matters.

There is increasing evidence that the use of antibiotics, both in infancy and thereafter, can contribute to obesity. This should not come as a surprise, because one of the chief reasons for the overuse of antibiotics is that they are so often fed to farm animals not to combat infection but solely to promote weight gain [8].

The PHE Review

In the light of the WHO and SACN reports, Public Health England (PHE), an executive agency sponsored by the Department of Health, carried out a review of the measures that could be taken to reduce the UK consumption of free sugars [3]. This was due to appear in the summer, but it did not. It turned out that the review had in fact been completed but the Secretary of State for Health (Jeremy Hunt, the same minister who provoked the junior hospital doctors into action) refused to publish it before the government announced its obesity strategy [9]. Neither the public nor the Commons Select Committee on Health, which specifically asked to see the report and was denied access, were intended to see the evidence until after the government had announced its plans – at which point it would be too late to have any influence. In the end, after the Chair of the Committee, the Conservative MP Sarah Wollaston, made the matter public, the review was published on 22 October. It proposes eight measures to help reduce the consumption of free sugars (See Box) and summarises the evidence on which these are based.

Actions recommended in the report of Public Health England (PHE).

1. Reduce and rebalance the number and type of price promotions in all retail outlets including supermarkets and convenience stores and the out of home sector (including restaurants, cafes and takeaways)

2. Significantly reduce opportunities to market and advertise high sugar food and drink products to children and adults across all media including digital platforms and through sponsorship

3. The setting of a clear definition for high sugar foods to aid with actions 1 and 2 above. Currently the only regulatory framework for doing this is via the Ofcom nutrient profiling model, which would benefit from being reviewed and strengthened

4. Introduction of a broad, structured and transparently monitored programme of gradual sugar reduction in everyday food and drink products, combined with reductions in portion size

5. Introduction of a price increase of a minimum of 10-20% on high sugar products through the use of a tax or levy such as on full sugar soft drinks, based on the emerging evidence of the impact of such measures in other countries

6. Adopt, implement and monitor the government buying standards for food and catering services (GBSF) across the public sector, including national and local government and the NHS to ensure provision and sale of healthier food and drinks in hospitals, leisure centres etc.

7. Ensure that accredited training in diet and health is routinely delivered to all of those who have opportunities to influence food choices in the catering, fitness and leisure sectors and others within local authorities

8. Continue to raise awareness of concerns around sugar levels in the diet to the public as well as health professionals, employers, the food industry etc, encourage action to reduce intakes and provide practical steps to help people lower their own and their families’ sugar intake

In fact, one of the review’s recommendations had been widely anticipated, a tax on sweets and soft drinks. The government has made it clear that they are opposed to this, arguing that it would have no effect and would in any case bear hardest on the poor.

But the evidence from Norway, Finland, Hungary, France and Mexico indicates that a tax on soft drinks can reduce consumption. In Mexico, a 10 % tax on sweetened drinks led to a 6 % decrease in sales. As for the effect on the least well off, this cannot have been uppermost in the mind of a government that only drew back from taking £1300 or more a year away from the lowest paid workers because the House of Lords was willing to provoke a constitutional crisis.

Of course if the tax were to have the desired effect of reducing consumption, most people, whether rich or poor, would be spending less rather than more on soft drinks. They would benefit both in their pockets and in their health. The losers would be the manufacturers, as they will be if any government action reduces their sales.

To conclude

The House of Commons Select Committee on Health has now published its report on Childhood Obesity [10]. Their recommendations are in general similar to those of the PHE, including a tax on sugary drinks. The government will not announce its obesity strategy until early in the New Year, so at the moment we know neither which recommendations it will accept nor which will become statutory and which will be left as suggestions that manufacturers can adopt or not as they see fit. In particular, the Prime Minister, like the food industry, is strongly opposed to the sugar tax, so this is highly unlikely to be implemented.

So far, the discussion in the media has been almost entirely about the sugar tax, but we must not allow the controversy it has generated to divert attention from all the other recommendations in the PHE review and the Select Committee’s Report. Cutting down on free sugars is a very cheap and easy way of improving our health. And there could be substantial savings for the government itself: obesity and its consequences are alone estimated to cost the NHS £5.1bn a year [3], so we’re talking big money.

Article first published 09/12/15


  1. “WHO calls on countries to reduce sugars intake among adults and children.” WHO press release, 4 March 2015,  25/11/15
  2. “Expert nutritionists recommend halving sugar in diet.” SACN press release, 17 July 2015,
  3. Tedstone A, Targett V, Allen R et al. Sugar Reduction: The Evidence for Action. Public Health England, London, 2015,
  4.  25/11/15
  5. Putnam J, Allshouse J. and  Kantor LS. US per capita food supply trends: more calories, refined carbohydrates and fats. Food Review 2002, 25 (3) Economic Research Service USDA. 25/11/15
  6. “What is the glycaemic index (GI)?” NHS Choices. 23 August 2015.
  7. “How one of the most obese countries on earth took on the soda giants.” Tina Rosenberg, The Guardian, 3 November 2015,
  8. Cho I, Yamanishi S, Cox L, Methé BA, Zavadil J, Kelvin L, Gao Z, Mahana D, Raju K, Teitler I, Ji H, Alekseyenko AV and Blaser MJ. Antibiotics in early life alter the murine colonic microbiome and adiposity. Nature 2012, 488, 622-629. Doi:10.1038/nature11400.
  9. “Hunt should practice what he preaches.” Sarah Wollaston, The Telegraph, 27 October, 2015,
  10. House of Commons Select Committee on Health. Report HC465: Childhood obesity – brave and bold action. The Stationary Office, London 2015,

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There are 2 comments on this article so far. Add your comment above.

Christine Comment left 10th December 2015 07:07:52
Just wonder if there is a metabolic difference in amount of consumed sugar between the good and bad bacteria?? Must be so, since I see a colossal effect on myself. And if so, definitely the GMO foods, which are promoting the BAD bacteria, do have a direct link to the sugar issue too, one could imagine...

Todd Millions Comment left 10th December 2015 18:06:34
I still have some problems with the -'free sugar' definition. As a for instance 'lactose'- pasteurized milk will shoot up blood sugar levels.But the same milk un-heated -won't.This is a physiological observation un-backed by measurements but its repeatable. Those contesting it tend to run on about how deadly dangerous unpasteurized milk is.Since I'm of a vintage and local where most of us were raised on fresh from teat milk-this amuses.Honey-same observations and even unpasteurized-its oft heated to that point for ease of handling.So in these examples I expect we are a few enzymes short of an accurate measurement set. But you know me-I try to be helpful(ahem). What about Malt sugars? I know-many 'accidentally' escaped GM strains contaminating all stocks. But-the herbicide and fungicide residue levels in and on the seeds Has to be low enough for them to be able to sprout. So a major source of toxic reactions(before the corn"fructose" is added) that otherwise can't be removed any more would be removed from testing and measurement for workers who aren't in the pay of international poisoneers.How often does that happen anymore?